This invention relates to a step-type training machine in which an exercise load is set by a heart rate, and by feeding back the heart rate during exercise, the braking force of a brake load means is automatically controlled so that the exercise load can be maintained at a level suited for the level of the physical strength of an individual exerciser. The invention also relates to a method of controlling this training machine.
More specifically, the invention relates to a step-type training machine in which the exerciser exercises under a predetermined load while detecting the pulse of the exerciser, and in accordance with data (e.g. the age, sex and weight) inputted before the training and various data (e.g. the exerciser's pulse) during the training, the step load is varied and controlled during the training so as to impart the optimum exercise load to the exerciser. In this manner, the exerciser can perform aerobic exercise efficiently and safely and also can perform isokinetic exercise in a stable manner because of the exercise speed control, thereby enabling the exerciser to execute the training without experiencing any excess load on the joints.
Recently, there have been developed various training machines intended for improving the physical strength of the young as well as the old. For example, there is known a training machine of a so-called upstairs-type in which there are provided a pair of right and left crank pedals which can be driven up and down, and the driving of the right and left crank pedals is transmitted to a load means such as a rheostatic brake, so that the up-and-down driving of the crank pedals can be controlled. In the conventional training machine of the upstairs-type, the speed of the up-and-down motion of the crank pedals is controlled by a braking force generated by a field current of a rheostatic brake load means which varies in proportion to the up-and-down driving speed of the crank pedals. Thus, the braking force of the rheostatic brake load means is not controlled by taking into consideration the weight, exercise efficiency, age, sex, physical strength, etc., of the exerciser.
In the conventional training machine of the upstairs-type, return mechanisms for the right and left crank pedals are constituted respectively by separate right and left springs, and therefore the reaction forces exerted by the springs respectively on the right and left feet of the exerciser are different from each other. Therefore, proper simulation of climbing stairs cannot be obtained.
Accordingly, in the conventional training machine of the upstairs type, the load of the rheostatic brake load means can not be adjusted in accordance with the level of the physical strength of the individual exerciser and in accordance with variations in physical conditions during the training, so that it has been difficult to set an effective exercise load for the exerciser. As a result, there have been problems that the training is either excessive or not sufficiently challenging.
Further, in the conventional upstairs type training machine, the reaction forces of the crank pedals differ depending on the position of the specific exerciser and the positions of the right and left feet of the exerciser. Further, there has been a problem with the durability of the springs.